Search

Abstract 2-(Quinuclidinium)-alkanocarboxylates co-crystallize with 2,6-dichloro-4-nitrophenol at the ratios 1:1 and 1:2 depending on the alkyl-chain lengths. The obtained complexes have been characterized by single-crystal X-ray diffraction, UV–vis, FTIR and NMR spectroscopy. The compounds 2-(quinuclidinium)-acetate and 2-(quinuclidinium)-propionate form complexes with 2,6-dichloro-4-nitrophenol at the stoichiometric ratio 1:2, while 2-(quinuclidinium)-butyrate and 2-(quinuclidinium)-valerate at ratio 1:1. Three crystal structures of compounds of these series were determined, but no single crystals of sufficient quality could be obtained of the 2-(quinuclidinium)-butyrate complex. The B3LYP/6-311++G(d,p) approach has been used to determine structures of their isolated molecules and to interpret the IR and UV–vis spectra. Diagrams of the HOMO and LUMO of molecules have been obtained. Graphical abstract Image 1 Highlights • Quiniclidinium-alkanocarboxylates form H B complexes with 2,6-dichloro-4-nitrophenol. • Lower homologues form molecular complexes at the 1:2 ratio. • Longer homologues form proton transfer 1:1 complexes. • Molecular structures were solved by X-ray diffraction and optimized by DFT methods. • UV–vis, FTIR and NMR spectra were measured. [ABSTRACT FROM AUTHOR]

The structures of 1,3-bis(3-hydroxymethylpyridinium)propane dibromide ( 1 ), 1,3-bis(3-hydroxymethylpyridinium)propane tetrabromozincate ( 2 ) and 1,3-bis(3-hydroxymethylpyridinium)propane tetrabromocuprate ( 3 ) have been studied by X-ray diffraction, DFT, FTIR, NMR and UV–vis methods. The crystal structures of three analogous compounds are significantly different: 1 is orthorhombic, space group Fdd 2, Z = 8, 2 is triclinic, space group P 1 ¯ , Z = 2 and 3 is monoclinic, space group C 2 /c , Z = 8. The bispyridinium dication in 1 lies on the special position on the 2-fold axis. Each 3-hydroxymethyl group forms an OH⋯Br hydrogen bond, and the dications combine into three-dimensional networks through numerous CH⋯Br bonds. The IR spectra of the dibromide of 1,3-bis(3-hydroxymethylpyridinium)propane ( 1 ) and its tetrabromometallates ( 2 and 3 ) were compared and their interpretation was confirmed by calculated spectra. UV–vis spectra for tetrabromocuprate salt ( 3 ) showed significant differences between solid-phase and water solution. [ABSTRACT FROM AUTHOR]

The structure of the complex of dimethylphenyl betaine (DMPB) with dichloroacetic acid (DCA) ( 1 ) has been investigated by X-ray diffraction, FTIR and Raman spectroscopy, and B3LYP/6-311 + + G(d,p) calculations. The crystal is monoclinic, space group P 2 1 . The acid is connected with betaine through the O H⋯O hydrogen bond of 2.480(2) Å. In the optimized structure the short, asymmetric O⋯O distance is 2.491 Å. FTIR spectrum shows a broad absorption in the 1500–400 cm −1 region characteristic of very short O H⋯O hydrogen bond caused by Fermi resonance between νOH and overtones of δOH and γOH. In the Raman spectrum this broad absorption is not observed. The potential energy distributions (PED) were used for the assignments of IR and Raman frequencies in the experimental and calculated spectra. The FTIR and Raman spectra of the crystal complex are consistent with the X-ray results. [ABSTRACT FROM AUTHOR]